Medical devices include devices designed to be implanted into a patient. Some examples of these implantable medical devices (IMDs) include cardiac function management (CFM) devices such as implantable pacemakers, implantable cardioverter defibrillators (ICDs), cardiac resynchronization therapy devices (CRTs), and devices that include a combination of such capabilities. The devices can be used to treat patients or subjects using electrical or other therapy or to aid a physician or caregiver in patient diagnosis through internal monitoring of a patient's condition. The devices may include one or more electrodes in communication with one or more sense amplifiers to monitor electrical heart activity within a patient, and often include one or more sensors to monitor one or more other internal patient parameters. Other examples of IMDs include implantable diagnostic devices, implantable drug delivery systems, or implantable devices with neural stimulation capability.
Medical devices also include wearable medical devices (WMDs) such as wearable cardioverter defibrillators (WCDs). WCDs are monitors that include surface electrodes. The surface electrodes are arranged to provide one or both of monitoring surface electrocardiograms (ECGs) and delivering cardioverter and defibrillator shock therapy.
Some IMDs include one or more sensors to monitor different physiologic aspects of the patient. Sensing of patient posture can provide information related to a patient's condition or disease. For example, a patient with congestive heart failure (CHF) may tend to sleep in an upward position as their condition worsens. Patient posture information may also be useful in other aspects of patient monitoring. For example, measurements taken by a medical device may vary with patient posture. Knowledge of the posture of the patient during the measurements may be useful to a caregiver in interpreting the device measurements.